Beamforming explained: How it makes wireless communication faster

Beamforming is a technique that focuses a wireless signal towards a specific receiving device, rather than having the signal spread in all directions from a broadcast antenna, as it normally would. The resulting more direct connection is faster and more reliable than it would be without beamforming.

Although the principles of beamforming have been known since the 1940s, in recent years beamforming technologies have introduced incremental improvements in Wi-Fi networking. Today, beamforming is crucial to the 5G networks that are just beginning to roll out.

How beamforming works

A single antenna broadcasting a wireless signal radiates that signal in all directions (unless it’s blocked by some physical object). That’s the nature of how electromagnetic waves work. But what if you wanted to focus that signal in a specific direction, to form a targeted beam of electromagnetic energy? One technique for doing this involves having multiple antennas in close proximity, all broadcasting the same signal at slightly different times. The overlapping waves will produce interference that in some areas is constructive (it makes the signal stronger) and in other areas is destructive (it makes the signal weaker, or undetectable). If executed correctly, this beamforming process can focus your signal where you want it to go.

nw wifi router traditional and beamformer foundational networking internet ojogabonitoo / Getty Images

The mathematics behind beamforming is very complex (the Math Encounters blog has an introduction, if you want a taste), but the application of beamforming techniques is not new. Any form of energy that travels in waves, including sound, can benefit from beamforming techniques; they were first developed to improve sonar during World War II and are still important to audio engineering. But we’re going to limit our discussion here to wireless networking and communications.  

Beamforming benefits and limitations

By focusing a signal in a specific direction, beamforming allows you deliver higher signal quality to your receiver — which in practice means faster information transfer and fewer errors — without needing to boost broadcast power. That’s basically the holy grail of wireless networking and the goal of most techniques for improving wireless communication. As an added benefit, because you aren’t broadcasting your signal in directions where it’s not needed, beamforming can reduce interference experienced by people trying to pick up other signals.

The limitations of beamforming mostly involve the computing resources it requires; there are many scenarios where the time and power resources required by beamforming calculations end up negating its advantages. But continuing improvements in processor power and efficiency have made beamforming techniques affordable enough to build into consumer networking equipment.

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